Section 5 1MAC309294-MB F
Control functions
308 RER620
Technical Manual
OOAP Mode - One Or All Phases
In this mode, if a single-phase fault is detected or picked up on one pole, a single-phase
trip will occur as in the case of OPUP mode. However, if a combination of two or three
phases pickup or detect a fault, then the RER620 will initiate a binary trip output to the
recloser for all three poles to trip.
For example, consider a situation where the distribution load has motors connected onto
the distribution line. If a single-phase fault occurred on any phase of the line, the RER620
should initiate a trip of all three phases, OOAP, to prevent the three-phase motors from
single phasing. A three-phase motor may continue to run with the loss of a single-phase,
but it will overheat. In addition, a stopped three-phase motor that is attempting to start with
the loss of a single-phase will cause overheating in the motor. For this application, a
distribution line with three-phase motors should implement OOAP on single-phase faults.
Some common examples:
• The recloser is set to trip on a single-phase fault in single-phase fashion, but lockout
in three-phase fashion (OOAP). A fault is detected and the recloser trips open on one
phase and will lockout on all three phases if the fault detected is a permanent fault.
• The recloser is set to trip on a single-phase fault (OOAP). A two-phase fault is
detected and the recloser trips open on all three-phases and will lockout on all three
phases if the fault detected is a permanent fault.
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